The development of the EDVAC computer system of 1948 is often cited as the beginning of the computer era. Since that time, computer systems have evolved into extremely sophisticated devices, and computer systems may be found in many different settings. Computer systems typically include a combination of hardware, such as semiconductors and circuit boards, and software, also known as computer programs. As advances in semiconductor processing and computer architecture push the performance of the computer hardware higher, more sophisticated and complex computer software has evolved to take advantage of the higher performance of the hardware, resulting in computer systems today that are much more powerful than just a few years ago.
As the sophistication and complexity of computer software increase, the more difficult the software is to debug. Bugs are problems, faults, or errors in a computer program. Locating, analyzing, and correcting suspected faults in a computer program is a process known as “debugging.” Typically, a programmer uses another computer program commonly known as a “debugger” to debug a program under development.
Conventional debuggers typically support two primary operations to assist a computer programmer. A first operation supported by conventional debuggers is a “step” function, which permits a computer programmer to process instructions (also known as “statements”) in a computer program one-by-one and see the results upon completion of each instruction. While the step operation provides a programmer with a large amount of information about a program during its execution, stepping through hundreds or thousands of program instructions can be extremely tedious and time consuming, and may require a programmer to step through many program instructions that are known to be error-free before a set of instructions to be analyzed are executed.
To address this difficulty, a second operation supported by conventional debuggers is a breakpoint operation, which permits a computer programmer to identify with a breakpoint a precise instruction for which it is desired to halt execution of a computer program during execution. As a result, when a computer program is executed by a debugger, the program executes in a normal fashion until a breakpoint is reached. The debugger then stops execution of the program and displays the results of the program to the programmer for analysis.
Typically, step operations and breakpoints are used together to simplify the debugging process. Specifically, a common debugging operation is to set a breakpoint at the beginning of a desired set of instructions to be analyzed and then begin executing the program. Once the breakpoint is reached, the debugger halts the program, and the programmer then steps through the desired set of instructions line-by-line using the step operation. Consequently, a programmer is able to more quickly isolate and analyze a particular set of instructions without having to step through irrelevant portions of a computer program.
Thus, once the programmer determines the appropriate places in the program and sets breakpoints at those appropriate places, the breakpoints can be a powerful tool. But, many breakpoints may be needed, and the breakpoints needed may change over time as the programmer gains more information about the problem being debugged. Hence, determining the appropriate places in the program, setting breakpoints at those places, and removing the breakpoints that are no longer needed can be an arduous task.
To make setting and removing breakpoints easier, some conventional debuggers have breakpoint groups. The primary use of these groups is to form a collection of breakpoints, which can be enabled and disabled all at once. Breakpoint groups allow the programmer to more rapidly adjust the debug environment and not be burdened by excessive and undesired breakpoint hits.
Unfortunately, breakpoint groups only allow a breakpoint to exist in one group at a time, and breakpoint groups have no relationship to one another, which limits the usefulness of the breakpoint groups. For example, consider a program with a large outer loop that contains breakpoints and a small inner loop that also contains breakpoints. There are times the user needs to only disable the breakpoints in the inner loop without disabling the breakpoints in the outer loop, and times when the user wants to disable both the breakpoints in the outer loop and the inner loop. Today, users must attempt to deal with this problem by either manipulating the breakpoints individually or creating multiple breakpoint groups and manipulating these groups individually while attempting to remember all the relationships between the groups.
Without a better way to manage breakpoints, the debugging of programs will continue to be a difficult and time-consuming task, which delays the introduction of software products and increases their costs. Although the aforementioned problems have been described in the context of loops, they may apply to any type of statements in a program to be debugged.